1. Field of the Invention
The present invention relates to a centering device for flat components, glass panels in particular, which can be surrounded at least along their lateral edges by a synthetic frame by injection/foaming or encapsulation.
2. Description of the Related Art
Such components in the form of glass panels for sliding roofs, rear windows, front windows, side windows or similar components are being installed increasingly in vehicles. In this situation the glass panel inside the roof or window opening is as large as possible such that the synthetic frame enclosing the glass panel made of a thermoplastic synthetic material or polyurethane foam material should be as narrow as possible. This synthetic frame of the glass sliding roof also serves to fasten mountings such as brackets to which the drive mechanism for opening the glass sliding roof is hinged, in particular when the glass sliding roof is utilized as a wind-up or turn-up roof or side panels with fastenings.
Substantial significance is attached to fastening the synthetic frame together with the mountings, as the glass panel of the glass sliding roof is to be mounted flush with the roof surface for aerodynamic reasons. The synthetic frame is according provided essentially on the circumferential edge and on a narrow region on the underside only of the synthetic frame. Also, the synthetic frame functions as mounting for a circumferential seal to ensure reliable sealing here.
A circumferential groove is also generally provided on the synthetic frame for sealing purposes. Yet this arrangement requires a very precise foaming or extrusion tool, since the distance between groove floor and the glass panel contour at the four circumferential side edges of the synthetic frame can be a few millimeters only on account of the preferred narrow structure, such that very precise positioning of the component, in particular the glass panel inside the tool, is required during manufacturing. The centering device required for fabrication should also not interfere with the run of foam of the synthetic material during the extrusion or foaming procedure so that the contact surfaces do not need to be oversized.
Furthermore, in the case of previous manufacturing processes employing customary manual centering in the foaming tool there has been the drawback of a higher cycle time and the high risk of accident. Additionally, the dimensional accuracy with use of mechanically coupled limit stops through the plurality of tools is often inadequate, in particular when elongations and thus certain dimensional inaccuracies can occur in the tool and with heat accumulation during manufacture. Because of this burrs, which require a large degree of retouching work, can occur at the edges of the synthetic frame.
The objective of the invention is accordingly to create a simply structured centering device for flat components, in particular for a glass panel, which avoids the present disadvantages and lowers tool costs in particular, as well as offering greater dimensional accuracy with less refinishing expense.
The synthetic frame for extruding/foaming can be manufactured simply and precisely centered by means of the proposed centering device. In particular, expensive mechanisms or couplings on the tool or for the centering device can be dispensed with in this case. The centering device is therefore essentially integrated into the foaming tool and exhibits a very simple structure. In addition, this effectively produces a very uniform run of foam, such that a complete wetting of the glass panel at the edges is attained. Also, the stability between the glass panel and the synthetic frame is consistently increased, such that the overall quality of the prefabricated part increases.
It is ensured in particular that the external contours of the component, in particular a glass sliding roof, are kept to exactly. This substantially lowers the expense for refinishing work on the external contour or deburring of the outer edges. In particular, with the simplest structure an exact relative assignment is achieved by centering the springs arranged in pairs, such that in a preferred embodiment of a glass sliding roof uniform seal installation and thus overall improved sealing of the roof opening is attained.